Scientists from the University of Southampton's School of Engineering Sciences, have been busy calculating the damage small asteroids could cause if the bits of space junk decide to come crashing down to earth on land or in the oceans. The researchers found that even an asteroid about 50 meters in diameter, could cause devastating property damage and loss of life.

Sleep tight: Robert E. Holmes Jr. is keeping watch.While we're all safely tucked up in bed, he's cranked back the roof on his backyard observatory in the sticks near Charleston. He then gets busy photographing the heavens using super-cooled cameras (it makes them work better) that he's strapped to a 2-ton telescope with a 32-inch mirror he built himself.Holmes hunts the heavens via computer and scans for telltale moving smudges of light; and maybe one day, one of those smudges just might turn out to be the cosmic bullet with Earth's name on it.

Objects with orbits that bring them near to Earth are potential killers. These objects, known as NEOs (Near-Earth Objects), are asteroids (see the astronomy question from week 19: Where is the planet between Mars and Jupiter?) or comets, which we can recognise when they are in the vicinity of the Sun by their characteristic tail. If these small heavenly bodies cross Earth's orbit while they are orbiting the Sun, it could lead to a collision - a so-called 'impact event'. Can such impacts be predicted?

Asteroid hunters have good news - and a challenge - for the rest of us.After an extensive search for asteroids a kilometre or more across, engineer Steve Chesley says that "we can now say with confidence that no asteroids large enough to cause such a global calamity are headed our way."

Newer, more powerful telescopes are allowing astronomers to see deeper into outer space and the closer they look, the more objects they are finding, which could have a direct impact with our planet - literally.

"There are about 6,000 NEO's that have been discovered so far. About 1,000 of those are objects that could run into the earth" - Astronomer Greg Novacek.

Death may be the only certainty in life - but how it comes about is anything but certain.Papers released from secret government archives this week revealed that in 1980 government scientists were told to calculate the exact chances of a Brit being killed by a falling asteroid.The study was an attempt to persuade the public that nuclear power was safe, and that there were plenty of other things that were statistically more lethal than a neighbourhood reactor.After much consideration, the men in white coats calculated that that one member of the public would be killed by an asteroid every 7,000 years.

A small asteroid that flamed out over northern Africa last week provided a light show of the sort that Earth's inhabitants see about once a year. But "Asteroid 2008 T3C" made history. It was the first "Near Earth Object" (NEO) to have its time and course of impact accurately forecast by astronomers around the world.

The successful prediction of a harmless asteroid impact over northern Africa yesterday bodes well for a Maui-based system in development to warn against potentially hazardous space rocks, a University of Hawaii astronomer contends.While boulders of various sizes routinely hit the Earth's atmosphere, this was the first time that astronomers saw one coming and accurately predicted the time and place of impact, UH astronomer David Tholen said yesterday.

In the early hours of yesterday morning a fireball exploded with the equivalent of a thousand tonnes of TNT over northern Sudan. The light was so intense that it lit up the sky like a full moon and an airliner 1,400km (870 miles) away reported seeing the bright flash.

Between five and 10 percent of Near Earth Objects could be comets impersonating asteroids, says Paul Abell, who is finding ways to unmask them. NEOs are objects whose orbits bring them in close proximity to Earth.Some NEOs could be dying comets, those that have lost most of the volatile materials that create their characteristic tails. Others could be dormant and might again display comet-like features after colliding with another object, said Abell, a Houston, Texas-based research scientist with the Planetary Science Institute.